It has previously been proposed to draw off loose ends of thread from a cone or cop on which thread or yarn is being wound by means of suction if the thread being wound should have broken or the thread supply to the cone or cop has become exhausted, so that a free loose end is being wound thereon. It is necessary to retrieve this end of yarn or thread and pull it off the cone on which it has been wound for some distance in order to permit it being knotted to the remaining thread, in case of breakage, or to connect the thread end with the beginning thread end portion of a new supply pirn.
A thread draw-off device intended to accomplish this object has been described in the literature (see Swiss Pat. No. 435,074) in which a pull-off roller is driven by a separate motor, the pull-off roller being brought into engagement with the cone or cop to remove and pluck off the ends of any loose thread. This arrangement is comparatively bulky and cannot be interchanged with previously customarily employed suction nozzles due to the space requirements thereof.
The referenced U.S. Pat. No. 4,169,563, by the inventor hereof, describes a suction apparatus in which two rollers are located within a nozzle. When a loose end of thread is to the plucked off the cone, the suction nozzle is brought into engagement with the cone in such a manner that a roller will engage the still rotating cone, and rotate another roller with an interrupted surface, for example a multiple worm thereon, in order to generate an intermittent, plucking engagement with the cone and thus pluck off the loose yarn or thread end therefrom, by providing axially shifting, moving, clamping positions between the contacting roller and the second roller with the interrupted surface.
It has been found that the apparatus of both types, although suitable to remove the yarn ends can still be improved since the plucking or pulling-off operation of the yarn end itself has led to yarn or thread breakage, particularly with fine yarn of low strength. Some difficulty also has been experienced in the loose yarn end or thread becoming entangled with the pulling off and sucking rollers and wrapping thereabout.